The present invention generally relates to a semiconductor device utilized in the TAB (Tape Automated Bonding) technique. More specifically, the present invention relates to a semiconductor device having a straight wall type bump, and also a manufacturing method thereof.
Referring now to FIG. 4, a description will be made of a conventional method for manufacturing a semiconductor device having a straight wall type bump.
In FIG. 4(a), both an electrode layer 2 and a protection film 3 are formed as predetermined patterns on a contact portion of a circuit element of a semiconductor substrate 1 (simply referred to as "substrate" hereinafter). Then, a barrier metal layer 4 is coated over an entire surface of the substrate. In FIG. 4(b), a thick resist layer 5 is applied onto the barrier metal layer 4, and then, this resist layer 5 is opened to define a contact region (namely, a bump forming region). In FIG. 4(c), a bump 6 is formed at the opened portion by way of the electrolytic plating, while using the above-described resist layer 5 as a mask. At this time, the barrier metal layer 4 coated over the entire surface of the substrate 1, functions as a common electrode. Then, in FIG. 4(d), the resist layer 5 is removed. In FIG. 4(e), another resist layer 7 functioning as another mask used to etch the barrier metal layer 4 is formed. Subsequently, in FIG. 4(f), after the barrier metal layer 4 is etched away while using the above-explained resist layer 7 as a mask, this resist layer 7 is removed. In accordance with the above-described processing steps, a straight wall type bump 6 is fabricated on the substrate 1.
However, the conventional semiconductor device with the above-described structure has the following problems.
That is to say, after the substrate on which the bump has been formed in accordance with the above-described manufacturing steps is separated/cut off in separate elements, these separated elements are connected to a film carrier by utilizing the well known wireless bonding technique for gang connections. Then, an epoxy resin or the like is potted to the elements connected to the film carrier. Thus, the respective elements are sealed by the epoxy resin. However, since this type of semiconductor device must be made very thin, sufficient moisture resistance can be hardly expected with employment of only such a sealing epoxy resin. Accordingly, although a specific protection film could be independently formed on the semiconductor elements, there is another problem that if a process step for forming such a specific protection film is additionally introduced into a series of the above-described manufacturing process, the entire manufacturing process becomes cumbersome and also the manufacturing cost is increased.